A study of planar chromophores in dichromophoric molecules by circular dichroism spectroscopy

Abstract

A synthesis of a series of enantiomerically pure polycyclic structures derived from (+)-(1S,5S)-bicyclo[3.3.1]nonane-2,6-dione was accomplished. Molecules containing single or two similar or different chromophores were obtained. Chiroptical properties of the synthesized chiral structures 2-5, and 7 having carbonyl, 1,2-methylenedioxybenzene, and indole chromophores were studied. The sign of the cotton effect was related to sector rules and the orientation of the planes containing chromophores in dichromophoric molecules possessing 1,2-methylenedioxybenzene and carbonyl or indole chromophores. Interaction of the chromophores in dichromophoric molecules was examined by CD spectroscopy; however, no direct evidence was obtained.

Synthesis of Diastereomeric Bicyclo[3.3.1]nonane Dibenzoyl Esters and Study of Their Chiroptical Properties

“…The (+)‐( 1S,5S )‐bicyclo[3.3.1]nonane‐2,6‐dione 1 was obtained in an enantiomerically pure form by kinetic resolution of the corresponding racemic diketone by using Baker's yeast . Synthesis of the respective monoprotected acetal 6,6‐ethylenedioxybicyclo[3.3.1]nonane‐2‐one 5 was performed following the procedure described earlier . The reduction of carbonyl groups in 1 as well as in 5 with sodium borohydride afforded exclusively endo ‐isomer as was proved for the racemic compound, leading to endo , endo ‐(+)‐( 1S,2R,5S,6R )‐2,6‐diol 2 and endo ‐2‐ol 6 , respectively.…”

“…The synthesis of starting enantiomerically pure (+)‐( 1S,5S )‐bicyclo[3.3.1]nonane‐2,6‐dione 1 and 6,6‐ethylenedioxybicyclo[3.3.1]nonane‐2‐one 5 was performed following the procedures described earlier . (+)‐( 1S,2R,5S,6R )‐bicyclo[3.3.1]nonane‐2,6‐diol 2 and endo ‐2‐ol 6 were prepared from the diketone 1 and monoprotected ketone 5 , respectively, by a reduction with sodium borohydride.…”

The Asymmetry is Derived from Mechanical Interlocking of Achiral Axle and Achiral Ring Components –Syntheses and Properties of Optically Pure [2]Rotaxanes–

“…In general, chirality that appeared in mechanically interlocked systems is attractive due to its unique structure having large and flexible asymmetric field owing to the high mobility of the components. However, the determination of the absolute configuration is therefore difficult when applying chromophore sector rules on CD spectal data [50,51]. Because absolute structures of these enantiomers 3 were not determined in this stage, resolved prerotaxanes were denoted as 31st and 32nd according to the eluted order in this condition.…”

Supramolecular Nanohelix Fabricated by Pillararene-Based Host–Guest System for Chirality Amplification, Transfer, and Circularly Polarized Luminescence in Water

“…Notably, during this interaction, the electron-withdrawing substituents containing in EsY might partially reduced the electron densities of WP5, which led to the lower intensity band of WP5 at 304 nm. 47 In addition, when higher amounts of EsY was loaded into WP5⊃(L-1 or D-1), the long fibers formed by WP5⊃(L-1 or D-1) were partially dissociated into short fibers in the resulting WP5⊃(L-1 or D-1)/EsY system via chromophoric dye stacking (evidenced by AFM and TEM results in the morphological section). This is another possible reason to decrease the CD signal of pillararene.…”